Kate Hughes was a senior partner at Cavalluzzo until her retirement from the full-time practice of law in June 2020. Kate is continuing to work with the firm on a number of cases as she winds down her practice. She was called to the bar in Ontario in 1987 and joined the firm in 1988. For over thirty years she represented nurses, teachers, midwives, psychologists, professional engineers, chiropractors, pharmacists and many other professionals and other workers in workplace disputes in all labour related forums. 

She provides legal services to professionals including representation at labour arbitration, the Ontario and Canada labour board and other tribunals, court judicial reviews and appeals, injunctions, advice regarding strikes and lockouts, professional regulation and discipline matters at regulatory colleges, inquests, advice regarding hospital privileges, civil litigation, pay equity and human rights matters.

Kate is a past President of the Canadian Association of Labour lawyers/Association canadienne des avocats du mouvement syndical, the association representing labour lawyers across Canada. She was a co-chair of the Ontario Human Rights Tribunal Practice Advisory Committee until the Committee was suspended indefinitely by the present Ontario government. She has frequently represented the Women’s Legal Education and Action Fund at the Supreme Court of Canada and Ontario Court of Appeal.  

Kate  was the recipient of the Award of Excellence In the Promotion of Women’s Equality in 2014. She was voted by her peers in the legal community as a “Best Lawyer” by L’Expert in 2019, as she was for every year for over the last decade.

Kate has repeatedly represented her clients at all levels of appeals, including repeatedly at the Supreme Court of Canada in December 2019 on an equality case for part-time workers (Ontario (Attorney General) v. Fraser, 2011 SCC 20 (CanLII), [2011] 2 SCR 3). She was counsel in the ground-breaking discrimination case known as Meiorin or the "female firefighter case" where the SCC accepted her argument and used it to establish the new test for discrimination (British Columbia v. British Columbia Government and Service Employees' Union (BCGSEU) (Meiorin) [1999] 3 S.C.R. 3). Other notable appeal cases are Talos (Talos v. Grand Erie District School Board, 2018 HRTO 680 (CanLII)), the OHRT lead case dealing with benefits after age 65; Johnstone (Canada (Attorney General) v. Johnstone, 2014 FCA 110 (CanLII)), the leading case on the human rights ground of family status; BMWE v. Canadian Pacific case (Brotherhood of Maintenance of Way Employees Canadian Pacific System Federation v. Canadian Pacific Ltd., 1996 CanLII 215 (SCC), [1996] 2 SCR 495), where she established the right of a union to obtain a court injunction against an employer for violating the collective agreement where there was no effective means to obtain interim remedies from an arbitrator.

Kate is especially well known for her work in human rights. In addition to being counsel on the leading cases of Meirion, Talos and Johnstone she was counsel on the leading case dealing with systemic human rights remedies (McKinnon v. the Ministry of Corrections), which has been upheld by the Court of Appeal (McKinnon v. Ontario (Correctional Services), 2007 HRTO 4 (CanLII)). She was lead counsel in a well known sexual harassment case against the Toronto Police Services Board (McWilliam v. Toronto Police Services Board, 2020 HRTO 574 (CanLII).

In the labour field, Kate is well known for a large number of successful lead cases on behalf of unions, including in the area of privacy including around medical forms, human rights issues around addictions, overturning unreasonable policies such as the “vaccinate or mask” policies in Ontario hospitals, accommodation issues, arbitrations regarding pension and deemed offsets, challenges to the use of agency workers, as well as hundreds of contract interpretation, discharge and discipline arbitrations and acting for unions in injunctions in strike and picketing cases.   

She has worked on several Public Inquiries, including representing Northern Irish families at the Blood Sunday Inquiry in Derry in the North of Ireland in September 2011.  Most recently she represented ONA at the Long-Term Care Inquiry in 2018-19 (chaired by The Honourable Justice Gillese).   

Kate is a frequent speaker on a variety of labour issues including discrimination in the workplace, harassment, duty of accommodation and professional discipline, health and education matters.

In addition to being called to the Ontario Bar in 1987, Kate is also called to the bar in British Columbia where she practiced labour law from 1993-98 before returning to Cavalluzzo. Prior to initially joining Cavalluzzo in 1988, Kate worked with the all-women labour law firm, Symes Kiteley & McIntyre in Toronto from 1985 to 1987. 


  • Call to the British Columbia Bar, 1993
  • Call to the Ontario Bar, 1987
  • Osgoode Hall Law School, LL.B., 1985


Best Lawyers Award Badge


  • Leading Practitioner in Workplace, Human Rights Law - Canadian Lexpert Legal Directory, 2015

Related Events

Event/Dec 5, 2017

Kate Hughes Speaks at Lancaster House Bargaining in the Broader Public Sector Conference

Kate will be speaking in a session covering the year's most important caselaw developments, focusing on good faith bargaining, disclosure, political s...
Event/Nov 19, 2014

Kate Hughes Speaks on Expert Strategies for Trial Preparation

Kate Hughes is speaking at the Ontario Bar Association's Professional Development Program on Expert Strategies for Trial Preparation.  Kate will ...
Event/Nov 5, 2014

Kate Hughes Speaks on "The Law and Practice Regarding Pickets, Strikes and Injunctions"

Kate Hughes is a speaker at a Law Society of Upper Canada live webcast entitled "The Law and Practice Regarding Pickets, Strikes, and Injunctions".&nb...
Event/Dec 9, 2013

Kate Hughes co-chairs the Law Society of Upper Canada's 2nd Annual Human Rights Summit

Kate Hughes co-chairs the Law Society of Upper Canada's 2nd Annual Human Rights Summit, with panels covering such issues as how family status is curre...

Related Publications

Publication/6 November 2014

The Law and Practice Regarding Pickets, Strikes and Injunctions

 The Law and Practice Regarding Pickets, Strikes and Injunctions
Publication/1 November 2013

Ignored and Misunderstood: Privacy Rights and Medical Information in the Canadian Workplace

Introduction In 1881, an English Appellate court said: "[I]t is well established that persons do not by virtue of their status as employees lose their...
Publication/29 April 2013

Role of the Health Professions Appeal and Review Board | Cavalluzzo

Role of the Health Professions Appeal and Review Board
Publication/2 November 2008

Enough is Enough: Recognizing & Responding to Violence in the Health Care Sector

Violence in the health care sector is pervasive and growing at a disturbing rate. For far too many health care workers (the majority being women and m...

Related Blogs

Blog/15 July 2020

$85,000 Awarded to Victim of Workplace Sexual Harassment

McWilliam v Toronto Police Services Board and Angelo Costa On June 30, 2020, the Human Rights Tribunal of Ontario (the “Tribunal”) release...
Blog/29 April 2019

Employees, Dependent Contractors and Independent Contractors: What’s the Difference?

What misclassification can mean to you

Workers who are misclassified as independent contractors instead of employees or dependent contractors could be deprived of important benefits. It's i...


Case/24 April 2020

Superior Court Judgment - ONA v Eatonville and Henley

A team of Cavalluzzo lawyers obtained an interlocutory injunction on behalf of ONA requiring four long-term care facilities to comply with government...
Case/10 January 2019

The Regional Municipality of Waterloo (Sunnyside Home) and Ontario Nurses' Association

Kate  Hughes and Tyler Boggs acted for the Ontario Nurses' Association in The Regional Municipality of Waterloo (Sunnyside Home) and Ontario...
Case/27 November 2018

Cambridge Memorial Hospital Ltd v Ontario Nurses Association

Cambridge Memorial Hospital Ltd v Ontario Nurses Association, 2011 CanLII 76525 (ON LA). The grievor has been receiving long term disability benefits ...
Case/12 November 2018

Ministry of Correctional Services v. McKinnon

Ministry of Correctional Services v. McKinnon, 2010 ONSC 3896 (Div. Ct.) This is an application for judicial review brought by the Ministry of Correct...